JPH0810190Y2 - Bonding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a bonding apparatus, and more particularly to a frame retainer for pressing a frame (hereinafter, referred to as a frame) such as a lead frame mounted on a bonding stage.

[Prior Art] Various types of frame holders for this type of bonding apparatus have been known.

For example, there is the one described in Japanese Utility Model Publication No. 53-159271. This is the frame retainer 10 as shown in Figs.
A plurality of notches 10b are provided around the void 10c, and the frame 1 is pressed by the projecting pieces 10a having a spring property protruding between the notches 10b.

This frame retainer 10 is made of iron-based material,
Since the periphery of the frame 1 is pressed down by the metal surface of the iron-based material in a certain region of the bonded area, the spring action of the protruding piece 10a causes a deflection 11 as shown in FIG. Press and press down.

In this frame retainer 10, if the number of pins of the lead 1n of the frame 1 is small, for example, the number of pins of about 14 to 42 is relatively small, the area per lead of the frame 1 is large and Since there is also a thickness, the entire lead 1n of the frame 1 can be surely pressed by the metal surface.

However, in the frame retainer 10 described above, the frame 1
Projection piece 10a so that each lead 1n of
It takes time and effort to slide the contact surface between the tip and the metal lead 1n, and the number of pins of the lead 1n has increased to about 100 to 200 pins as the integration of semiconductor parts has advanced in recent years.
If the thickness of 1n is also small, the width of the lead 1n and the gap between the leads 1n are small, and the IC chip (semiconductor) is downsized, there is a problem that the leads 1n cannot be reliably held down.

Therefore, in order to hold down the frame even if the number of pins of the lead 1n is increased, a frame presser that attaches a sealing material and holds down the entire periphery of the lead 1n is used as the frame holding member.

As this seal material, VALQUA (registered trademark) CODE SEAL (registered trademark) <SOFT> manufactured by Nippon VALQUA CORPORATION is used. This is based on an ethylene tetrafluoride resin as a main component, and is flexible and rich in toughness. It can be used in the range of -240 ° C to + 260 ° C.

[Problems to be solved by the invention] However, as the integration of semiconductor components has advanced in recent years, the number of pins of the lead 1n has increased, the thickness of the lead 1n is thin, and the width of the lead 1n and the gap between the leads 1n are small. When bonding the broken frame, if the overheating temperature of the bonding stage is the same as the conventional one and the crimping energy of the ultrasonic transducer is made equal to that of the conventional one with a small number of lead 1n pins, cracking, damage, etc. during crimping will occur. There is a drawback that damage occurs. Therefore, by increasing the temperature of the bonding stage to about 300 ° C. to 350 ° C., there is a tendency to reduce the pressure bonding energy of the ultrasonic transducer to obtain the same pressure bonding effect.

However, in the previously used VALQUA (registered trademark) Code Seal (registered trademark) <soft> of Nippon VALQUA INDUSTRY CO., LTD., Since the allowable heat resistance temperature is around 260 ° C, heat curing occurs when the temperature is raised above this temperature. However, there is a drawback that the holding effect of the frame is sharply lowered and the durability is lowered in proportion to the temperature rise. In addition, since the sealing material generally has both high electrical insulation and heat insulation properties, static electricity is unavoidable when the frame is pressed through it, which may cause electrostatic damage to the IC chip or dust. It is one of the causes. Further, when a sealant is provided on the heater block side to press the frame, it takes a long time to raise the temperature due to poor heat conduction, resulting in a decrease in productivity. Furthermore, if you press the frame with the number of pins of the lead 1n of about 100 to 200 pins formed at one time of bonding and perform bonding, the number of lead terminals to be bonded increases and the time required for the entire bonding also increases. In addition, since the bonding is performed continuously, the flatness and parallelism change due to the thermal expansion of the frame retainer, etc., and the force pressing around the parts to be bonded changes, and each lead is firmly attached. It has the drawback that it cannot be pressed down.

Therefore, the present invention has been made in view of the above-mentioned drawbacks of the prior art, and presses each lead of the frame to make each force substantially uniform and also copes with the thermal expansion of metal by continuous bonding for a long time. Using a heat-resistant compression-resilient graphite compact, the pressing force of the frame can be kept constant even when continuous bonding is performed for a long time, and the occurrence of defects due to static electricity and dust is high and productivity is high. An object is to provide a bonding apparatus.

[Means for Solving the Problem] In the bonding apparatus according to the present invention, a compression-restoring graphite molded body is provided on a pressing surface of a frame pressing member that presses a frame positioned on a bonding stage so as to protrude from the pressing surface. It is composed of.

Also, the bonding apparatus according to the present invention forms an opening having a predetermined size at the center of the pressing surface of the frame presser for pressing the frame positioned on the bonding stage, and forming a predetermined depth around the opening. A concave portion having the above is formed, and a compression-restorable graphite molded body is provided in the concave portion so as to project from the pressing surface.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that components having the same configuration and function as the conventional device will be described using the same reference numerals.

FIG. 1 is a partial sectional view showing a state in which a lead frame is pressed by a frame press of a bonding apparatus according to the present invention.

In the figure, a lead frame 1 (hereinafter, referred to as a frame) is carried and positioned by a carrying mechanism (not shown) on a heater block 2 which constitutes a bonding stage. A tubular heater is built in the heater block 2, and the frame 1 positioned on the heater block 2 is overheated in the range of about 300 ° C to 350 ° C. The frame retainer 3 is pressed from above the frame 1 via the compression-restorable graphite molded body 4 fixed to the frame retainer 3 to press the lead 1n of the frame 1 onto the heater block 2. This frame retainer 3 has a mounting hole in the mounting member (not shown).
It is fixed by fixing means such as bolts by 3d. The frame retainer 3 is moved in the ZZ 'direction by an elevating mechanism (not shown) (or it may be configured to rotate about an axis).
After being positioned so that the frame 1 is positioned on the heater block 2, the frame 1 is moved downward (Z 'direction) and pressed.

FIG. 2 is a perspective view of the frame retainer 3 as seen from the back side, and FIG. 3 is a partially enlarged sectional view of the opening 3a and the like of the frame retainer 3.

An opening 3a having a predetermined size is formed in front of the frame retainer 3 shown in FIG. Between the lead 1n of the frame 1 positioned by the bonding head (not shown) located above through the opening 3a and the pad on the IC chip (not shown) arranged substantially in the center of the opening 3a. Bonding connection is made by wires. Also,
A perspective portion 3b is formed around the opening 3a on the upper side in FIG. 1 (the back side in FIG. 3). Also, this inclined portion 3b
A concave portion 3c is formed in the periphery of the side facing to, and the compression-restorable graphite molded body 4 having a predetermined width and thickness is fixed to the concave portion 3c. The thickness of the compression-restorable graphite molded body 4 needs to be at least thicker than the thickness t _{0 of the} recess 3c shown in FIG. 3 and protruding from the pressing surface 3e.

This compression-restorable graphite molded body 4 was molded by using a suitable binder to mold graphite particles in which a large number of small cell-shaped structures each having a thin carbon layer surface are isotropically formed, and then heat-treating the molded graphite particles. It has a property that the volume is compressed when a load is applied, but it is restored to the original volume when the load is removed. Further, this compression-recovery property is a property that is exhibited because the molded body is composed of the above-mentioned many graphite particles having a small cell-like structure, and cannot be obtained by the conventional graphite molded body. is there.

The compression-restorable graphite compact according to the present invention does not have tensile elasticity like rubber, but exhibits the above properties only when compressed. Such a compression-restorable graphite molded product can also be manufactured by the method described in JP-A-02-172809 and JP-A-02-208214.

As the compression-restorable graphite compact used in this example, one having the following characteristics is used.

Further, in the conventional frame presser, even when the cord seal (registered trademark) having a higher heat resistance temperature than the elastic body such as rubber was used, the heating up to about 260 ° C. was the limit, but in the frame presser of this embodiment, Since the compression-restorable graphite molded body is used, sufficient heat resistance can be obtained even in the state of being heated at about 300 ° C. or higher for a long time.

Further, since this compression-recoverable graphite molded body 4 has an appropriate compression-recovery force, it can be formed into a rod shape having a predetermined length as described in the dimension column of the above table, so that the molding is easy. Since it is sufficient to fix the concave portion 3c to the concave portion 3c with an adhesive or the like, it is possible to easily replace the concave portion 3c with a new one. Further, even if the lead 1n bends, warps, or changes in parallelism and flatness due to thermal expansion of the bonding stage and the frame retainer 3 occur, they can be uniformly suppressed by the compression restoring force of the compression restoring graphite molded body 4. . Furthermore, this compression restoring force does not change even during continuous work for a long time.

As described above, the surfacing is not necessary, and the time required for the lapping work and the like can be saved.

 The operation of the device having the above configuration will be described.

As shown in FIG. 1, when the frame 1 is conveyed and positioned by the conveying device onto the heater block 2 serving as a bonding stage, the frame retainer 3 descends in the Z ′ direction to compress the frame 1 into the compression-restorable graphite molded body 4. The lead 1n is uniformly pressed by a predetermined pressing force via. At this time, since the compression-restorable graphite molded body 4 has an appropriate compression-restoring force, variations in the leads 1n of the frame 1, for example, bending of the leads 1n,
Even if there is a warp etc., it can be pressed in close contact,
While the frame 1 on the heater block 2 is heated, the bonding work is performed by a bonding head (not shown). After this bonding work is completed, press the frame 3
Rises in the Z direction and stands by, and the frame 1 on the heater block 2 is intermittently sent by one frame to position the next IC chip. Then, the frame presser 3 descends and presses in the Z'direction as described above.

The bonding work is performed by repeating the above steps.

Next, a second embodiment will be described with reference to FIG. It should be noted that description of the same configurations and functions as those in FIGS. 1 to 3 will be omitted, and only different points will be described below.

4, in the vicinity of the opening side edge 3f of the pressing surface 3e of the frame presser 3, a fitting frame 5 having a groove having a wedge-shaped cross section is provided around the opening (substantially the same as the opening 3a in FIG. 2). Is formed.

The compression-restoring graphite molded body 4 formed in a rod shape with a predetermined length is fitted into the groove of the fitting frame 5 to form a frame retainer. In this frame holder, since the compression-restorable graphite molded body 4 is fitted in the groove of the fitting frame 5 having a wedge-shaped cross section,
It can be performed without using an adhesive. Therefore, even if the downward pressure bonding work is repeated, the compression-restorable graphite molded body 4 does not fall off from the frame holder.

In this embodiment, the compression-restoring graphite molded body 4 is provided on the pressing surface 3e side of the frame retainer 3, but the compression-restoring graphite molded body is provided on the surface facing the frame pressing surface 3e on the bonding stage. 4 may be provided,
Alternatively, the compression-restorable graphite molded body 4 may be provided on both of them.

[Effects of the Invention] As described above, the present invention has the following effects.

That is, firstly, according to the present invention, since the compression-restoring graphite molded body having heat resistance is used for the frame retainer, the temperature is about 300 ° C to 3 ° C.
Even in the case of a multi-pin bonded component within the range of 50 ° C, there is an effect that each lead of the frame can be surely pressed by a uniform pressing force.

Secondly, according to the present invention, the component to be bonded is pressed through the compression-restorable graphite compact,
This has the effect that the flatness of the frame retainer does not change due to thermal expansion or the like, and the force of pressing around the bonded component does not change.

Thirdly, according to the present invention, the compression-restorable graphite compact is
Since it has good electrical conductivity, there is no risk of electrostatic charge by pressing the bonded parts via this compression-resilient graphite molding, and the effect of preventing accidents due to electrostatic breakdown of the IC chip or dust adhesion due to charging. There is.

Fourthly, according to the present invention, the compression-restorable graphite compact is
Since the heat conductivity is also good, it does not hinder the heat conduction to the frame and has the effect of preventing the productivity from decreasing.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a state where a lead frame is pressed by a frame presser of a bonding apparatus according to the present invention, FIG. 2 is a perspective view of the frame presser shown in FIG. 2 is a partially enlarged cross-sectional view of the opening of the frame retainer in FIG. 2, FIG. 4 is an explanatory view showing another embodiment of the present invention, and FIGS. 5 and 6 are views of a conventional bonding apparatus. It is a perspective view of a frame retainer, and its sectional view. 1 ... Lead frame, 2 ... Heater block, 3 ...
Frame retainer, 3a …… Opening part, 3b …… Inclined part, 3c …… Recessed part, 3d …… Mounting hole, 3e …… Pressing surface, 3f …… Opening side edge, 4
...... Compression-restorable graphite molded product, 10 …… Frame holder.

Claims (3)

[Scope of utility model registration request] 1. A bonding apparatus for performing thermocompression bonding by pressing a frame positioned on a bonding stage with a frame presser, the pressing surface being a pressing surface of a frame presser for pressing the frame positioned on the bonding stage. A bonding apparatus characterized in that a compression-restorable graphite molded body is provided so as to project further. 2. A bonding apparatus for performing thermocompression bonding by pressing a frame positioned on a bonding stage with a frame presser, wherein a predetermined amount is provided at the center of the pressing surface of the frame presser for pressing the frame positioned on the bonding stage. An opening having a size is formed, a recess having a predetermined depth is formed around the opening, and a compression-restorable graphite molded body is provided in the recess so as to project from the pressing surface. Bonding device. 3. A recess having a predetermined depth formed around the opening has a wide wedge-shaped cross section at the bottom, and a compression-restoring graphite molded body is fitted in the recess so as to project from the pressing surface. The bonding apparatus according to claim 2, characterized in that: